add Cloud liquid water path to Atmospheric variables (table 1-01-01)

[amilan17]

Initial request

Cloud liquid water (CLW) total column was updated in OSCAR/Requirements in the summer of 2024. This issue is an attempt to align the code with WIGOS metadata.

add Cloud liquid water path to Atmospheric variables (table 1-01-01)

Amendment details

Name	Description
Cloud liquid water path	2D Field of atmospheric water in the liquid phase (precipitating or not), integrated over the total column.

Requestor(s)

GCOS, OSCAR Requirements, @kpremec

Stakeholder(s)

Enter list of stakeholder(s).

Applications or Systems

• OSCAR/Surface
• OSCAR/requirements
• Radar/DB
• OceanOPS
• WHOS
• WDQMS
• GBON Compliance Monitor
• Other

Expected impact of change

None

Collaborators

No response

References

See comment in: https://space.oscar.wmo.int/variables/view/cloud_liquid_water_clw_total_column

Comments

maybe related to Water vapour which does not have a definition

Publication(s)

Example: Manual on Codes (WMO-No. 306), Volume I.3, WMO Codes Registry, Code table 1-01-01

Validation

No response

[amilan17]

https://github.com/wmo-im/tt-wigosmd/wiki/Meeting.2024.10.24 notes:
@joergklausen taking responsiblity

[joergklausen]

Similar terms:

• Cloud Liquid Water Content - Cloud Liquid Water is a measure of the total liquid water contained in a cloud in a vertical column of atmosphere.
• Liquid water path [gm/m^2]: It is a measure of the total amount of liquid water present in the column. A retrieved quantity from the microwave radiometer.
• The total amount of liquid water per unit area in the column of air from cloud base to top height is called liquid water path (LWP)

The primary issue with the proposed term 'Cloud liquid water path' is the constraint 'cloud' of the more general term 'liquid water path', which is not evident from the proposed description. Liquid water can exist in the atmosphere outside of (identifiable) clouds. The term 'cloud' is restricted to liquid water or ice particles suspended in air above a certain elevation above ground, while fog also contributes to the total columnar liquid water content.

To be consistent, rather than just adding the proposed term, it is suggested to add 2 terms, namely:

1. Total atmospheric liquid water path = vertically integrated liquid water content of the atmosphere above a specified location on Earth
2. Cloud liquid water path = vertically integrated liquid water content of a cloud above a specified location on Earth.

The originator of the issue @kpremec is requested to clarify which of these 2 variables is meant by the variable 'Cloud liquid water path'. Either the term or the description needs to be updated.

[amilan17]

https://github.com/wmo-im/tt-wigosmd/wiki/Meeting.2024.11.21 notes:
Joerg proposes two terms instead of one

[amilan17]

https://github.com/wmo-im/tt-wigosmd/wiki/Meeting.2024.12.13 notes:
@amilan17 help facilitate coordination with GCOS on recommendation above

[amilan17]

Related WIGOS codes:

• 373 | Cloud liquid water (CLW) | Atmospheric water in the liquid phase (precipitating or not).
• 327 | Cloud ice | Atmospheric water in the solid phase (precipitating or not).

@kpremec will work with GCOS